In cables requiring high tear resistance and great alternating bending strength, electric tinsel conductors are conventionally used as inner conductors. In electric tinsel conductors, tin or silver plated copper tinsel or metal foil is wound helically on a carrier fiber. The carrier fiber is cotton or synthetic fibers. When such conventional cables are exposed to moisture, as frequently occurs in connection with medical apparatus, the tinsel strip or metal foil frequently corrodes after only a relatively short time. This corrosion can be attributed to penetrating moisture.
Until this time, there has been no successful and reliable mechanism for preventing the penetration of moisture into the cable. Therefore, the defective and insufficient corrosion resistance has been accepted in order to obtain the great tear resistance and excellent alternating bending strength of such conventional cables.